package utils;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

public class ClassUtil {
	/**
	 * Scans all classes accessible from the context class loader which belong to the given package and subpackages.
	 * 
	 */
	public static Class[] getClasses(String packageName) {
		ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
		assert classLoader != null;
		String path = packageName.replace('.', '/');
		ArrayList<Class> classes;
		try {
			Enumeration<URL> resources = classLoader.getResources(path);
			List<File> dirs = new ArrayList<File>();
			while (resources.hasMoreElements()) {
				URL resource = resources.nextElement();
				dirs.add(new File(resource.getFile()));
			}
			classes = new ArrayList<Class>();
			for (File directory : dirs) {
				classes.addAll(findClasses(directory, packageName));
			}
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
		return classes.toArray(new Class[classes.size()]);
	}

	/**
	 * Recursive method used to find all classes in a given directory and subdirs.
	 */
	private static List<Class> findClasses(File directory, String packageName) throws ClassNotFoundException {
		List<Class> classes = new ArrayList<Class>();
		if (!directory.exists()) {
			return classes;
		}
		File[] files = directory.listFiles();
		for (File file : files) {
			if (file.isDirectory()) {
				assert !file.getName().contains(".");
				classes.addAll(findClasses(file, packageName + "." + file.getName()));
			} else if (file.getName().endsWith(".class")) {
				classes.add(Class.forName(packageName + '.' + file.getName().substring(0, file.getName().length() - 6)));
			}
		}
		return classes;
	}

}
